Sunderland boss Paolo di Canio is delighted with the impact of stand-in skipper John O'Shea.
O'Shea has filled in with Lee Cattermole out due to injury.
Di Canio said: "I didn't have any doubts about him because in a natural way, he is always smiling. In the morning, he is the first always to come out for the warm-up before the training session.
"He is at the top of the group, he always tries to encourage the others. He is always in action, always on his toes, which is important.
"When I am talking about tactical situations, sometimes you see the young players with their mouths open looking at the sky; John O'Shea always stays alive and listens so he can go into action straight away.
"It's crucial because you can be the best manager you can, but in the dressing room if you have one, two - I don't want to say 10 - but one, two players who deliver the same message, if the others still haven't received that message and they are going to forget, it's crucial.
"He is positive, intelligent, so he is the leader."